The present invention relates to hydrophilic coatings and, more particularly, to a hydrophilic coating composition for enhanced biocide dissolution.
Heat exchangers are widely known and used in, for example, space stations, space vehicles, and terrestrial cooling systems. Conventional heat exchangers include slurper bars coated with an antimicrobial hydrophilic coating that inhibits growth of micro-organisms and promotes condensation of condensed water from passing air. A vacuum source evacuates a passage in the slurper bars to collect the condensed water and prevent formation of water droplets that may otherwise reduce airflow. The condensed water is collected downstream, purified, and reused.
Conventional antimicrobial hydrophilic coatings are typically applied as a slurry to the slurper bars and cured at elevated temperatures. Upon curing, the slurry forms the antimicrobial hydrophilic coating, which wicks away condensed moisture on the slurper bars. Typical antimicrobial hydrophilic coatings include a matrix of potassium silicate and/or borosilicate in which a biocide resides, typically silver oxide. Disadvantageously, potassium silicate and/or borosilicate matrices are prone to cracking, flaking, and dissolution of the biocide into the condensed water. The condensed water and dissolved biocide collect downstream, where the zinc oxide often precipitates out of solution and forms a build-up on purifiers, filters, or other components. The build-up may inhibit proper operation of the cooling system.
Accordingly, an antimicrobial hydrophilic coating composition that is less prone to cracking, flaking, and biocide dissolution is needed.